Process of making an avocado food product



Patented Jan. 10, 1950 1 Laurence E.liarrisong-lFallbiiooknCalifi,@assignor.

phone-halfto-Maude J.;Anderson, I-Iol'lister,

Calif.

: .iNo Drawing. Al licatiorrAprit 19";1948;

Serial No. 21-58 "4 Claims; (Cl. 99 -154) -T hisinvention-relates to aprocess of -making apreserved avocadotood product. v

-Thisapplioatiomis a continuation-in-part of my-application. Ser:-No.-702,852, filed October 11 1946, now abandoned.

-Thenterm-flavccado meat will be used herein to-.designatethe: edibleportion or pulp oithe avocado-fruit, Withi-th6 skin-and seeds removed.

:Thea'principal object of this invention is to produce an-avocado=.-foodproduct of cheese-like. consistency-,..retaining the:major portion of the initialefood value of ripe avocado-meat in a stateof. preservation that imparts excellent keeping qualities. thereto,whereby theproduct may be kept for long-periodswithoutdeleterious changein colon-consistency, food-value or flavor.

A- fur-ther object-is toproduceanavocado food product of cheese-likeconsistency and good keeping qualities; retaining substantially thenatural color and pleasing appearance ofiresh avocado meat, andhavinghighly palatable flavor-characteristics.

Aparticular. object of. the invention is to provide for the treatmentof..the avocado meat in. such manner as to prevent darkening ordiscoloration of the resulting food product.

Another. important object" of the invention is to providean. avocadofood product having. a considerably higher oil' contentv that theinitial avocado meat, and, particularly, to so increase the oil contentas to preserve-the food product andgreatly increase its keepingqualities without. requiring the presence of any other preservative.agenti Furthermore,- since a large proportion of the. food value ofavocadomeat is contained in the oil, the increase in oil. contentenhances the 'food. value of. the product.

A.f-urthe'rfobject. is to provide a process -for the production. of afood product having the abovementioned desirable characteristics and of.substantially. uniform quality and consistency, in spite.ofconsider'able' variations in oil content or other characteristics ofthe initial avocado meat.

The production of. asatis'f'actory preserved foodl productifrom.avocados'presents problems quite" different fromthose encountered in thepreservation of other fruits or vegetables.

Preservation by any method. involving cooking or heating at elevatedtemperature is entirely unsatisfactory because of theresultinghighlyunpalatableflavor and. also because cooking tends to cause the'avocadomeat to disintegrate or becomesoft and'mushy, so that; theproduct is not only of'p'oor flavor'but also'has an undesirableappearanceor consistency.

' somewhat. above or somewhat below the abovementioned range, but thebestresults aregeneral- 2. Ordinary pickling: methodssuch. as areacomemonly employed with: other. fruits. .or vegetables, in whichlthe:resultingproduct is preserved: and

retained in a. liquid. or semirzliquidi vehicle, are" alsounsatisfactory because in such processes also 1 the fragile qualityofthe-avocadomeat causes it to. disintegrate. OEibBCOmBJ softland mushy,S01

that. the product is, quite unsatisfactory in appearance. and.consistency.

One of the-mostsseriesxobstacles to the production of a preservedavocado food product is the discoloration 0t thewavocadomeat; which:darkensrapidly and: soonnbecomesxquite black". ons exposure to air.Thisudiscolora'tion iszbelieved'to': be. due to the action ofianenzyme-present in; the avocadoimeatawh-ich promotes oxidation and;

resulting darkening of the: natural: ;coloringam-atmeat.

I have 1 discovered that-the discoloration of I avocado. meat can: bezcompletelyprevented, and

eliminated. by subjecting it to a. properly conducted lactic vacidvacilli fermentation, pre-. sumablydue to destruction of. the :enzymethat normally promotes-tench: discoloratiom lhaves;

found. further; that-this lactic acidnbacilli.

fermentation can best bar-carried out: at about normal atmospherictemperature, such as from about to. about F., inthe presence of a.

salt solution 'or brine-of such. strengthas to -in-- hibit thedevelopment of harmful. bacteria, while. permitting the-lacticacidbacilli to multiply. rapidly and thuscause the lactic. .acid fermenta-.-

tion to progress at arsatisfactory rate.. 'Thetemperature duringfermentation .is. note-especially critical; it .mayt beconductedattemperatures ly obtained when the:temperatureis keptwithinthis range.

The. lactic acid. fermentation is .general1y;conducted. in-v thepresence of a-sodum chloride brinehaving. a specific gravity betweenabout 10 and. 20 Bl, and preferably about 12 to 15 B.- Inv a brine ofthis. concentration,.the fermentation. progresses rapidly, generallycausing the acidity to increase to; alpI-I below. dwi'thin about 48hours,

and fermentation is generally'substantially complete within about Oneortwo Weeks... In. most. cases,. a fermentation period of about. ten totwelve days givesthe bestresu1ts.-. 7 I

factor in the good keeping quality of the product. Y

Following fermentation, the avocado meats are subjected to contactwithsterile water, preferably at about normal temperature, to leach outexcess salt and reduce the salt content to a palatable level, such asabout 1 to 2%; The fermentation and leaching steps may advantageously beconducted by placing the avocado meats in closely woven cotton bags thatare pervious to water, immersing them in brine inoculated with lacticacid bacilli until fermentation is complete, then removing the bags andtheir contents fromthe brine and immersing them in fresh water to leachout excess salt as noted above.

At this stage, the treated avocado meats are in a somewhat disintegratedcondition and are partly reduced to a soft, pulpy mass. The treatedproduct contains a considerable amount of water and, in this condition,is perishable and subject to deterioration if kept in this conditionbecause the lowering of the salt content to the palatable level hasremoved the preservative effect of the salt.

In fresh ripe avocados, the oil content is highly emulsified with water,and if untreated avocado meats are subjected to pressure to expressliquid therefrom, the expressed liquid is an oil-water emulsioncontaining oil and water in approximately equal proportions. I havefurther discovered, however, that by subjecting the avocado meats tolactic acid bacilli fermentation followed by leaching with water, asdescribed above, the oil and water are largely freed from theiremulsifiedcondition, so that by subjecting the treated 7 material to apressing operation while contained in a liquid-pervious container whichretains the solid constituents therein, a considerable portion I of thewater content may be expressed with relatively little expression of oil.If the pressure is continued, the oil-water ratio of the expressedliquid increases, until the proportion of oil in the liquid beingexpressed equals, and finally exceeds,

'the proportion of water.

I prefer to continue the pressing operation only to about the point whenthe oil is being expressed in about equal proportion to the water, whichI term the oil-water level point. At this stage, alarge proportion ofthe water contained in the product following fermentation and leachinghas been removed, while a high proportion of the oil content isretained. V

The resulting product has a cheese-like consistency, resembling that ofAmerican cream cheese. The product is slightly acid, generally having apH between and 6, and this acidity remains substantially constant duringsubsequent aging and storage, particularly if kept at a modtive colorthat does not darken on standing, and contains the major portion of theinitial food value of the avocado meats. It is well preserved V and maybe kept for long periods without any deleterious change in flavor, coloror consistency, due apparently to the preservative effect of theincreased oil content. In fact, the product improves somewhat on agingat a moderately low temperature such as about 40 F., and I prefer tostore it for aging at such temperature for a period of a few weeks orlonger. It is also amenable to processing to form other food products,as by mixing with milk cheese or by adding other vegetable flavoringmaterials.

The following is a more specific description of a preferred example ofthe process.

Ripe avocados are peeled and cut and the seeds are removed therefrom,and the avocado meats run culls contained 38% oil, 16% solids, and 46%are then preferably washed. Twenty-five pounds of the sliced avocadomeats are placed in a closely woven cotton bag, and the bag and thecontained avocado meats are submerged in ten gallons of brine, such as a14 B. sodium chloride solution. The brine is inoculated with aboutonehalf pint of lactic acid bacilli culture and a temperature of 70 F.is maintained. Fermentation proceeds rapidly, and the pH of the brine isgenerally reduced to about 5.4 within 48 to 72 hours. The pH of thebrine is preferably determined daily to follow the course of thefermentation. The concentration and temperature of the brine are alsoobserved regularly and adjusted, if necessary, to maintain themsubstantially constant.

Fermentation is continued for about ten to twelve days, when it issubstantially complete.

The bag containing the fermented avocado depending upon the size andphysical conditionof the pieces of fermented avocado meat. The

bag is then removed from the water and allowed to drain for a shortperiod.

The top of the bag is then folded over so that the avocado meat can notescape therefrom when pressure is applied, and the bag containing theavocado meat is then subjected to mechanical pressure in any suitableform of press, to express liquid therefrom. The pressure is preferablyapplied slowly, and gradually increased. The liquid first expressedconsists principally of water and contains only a relatively smallproportion of oil. The proportion of oil to water in the liquid beingexpressed increases as the water content of the product decreases, andthe expressing of liquid is continued until the rate of expression ofoil becomes about equal to the rate of expression of water. 7

The bag is then removed from the press, and the resulting material,which is the food product of the present invention, is removed from thebag. It is then preferably placed in a suitable container and placed instorage for aging at about When using well ripened avocadoes, and bycareful control of the process, I am able to prois dependent uponvariable'factors, particularly a the quality and maturity of theavocados. For

example, a product prepared from average field water, while a productprepared from very immature avocados contained only 29% oil, 17% solids,and 54% water. The latter product was inferior in every respect, asmight be expected in view of the highly fibrous structure and low oilcontent of immature avocados. I prefer, therefore, to use well ripenedavocados and to produce a finished product having an oil content as near40% as practical considerations will allow, thus obtaining a productthat is of the highest quality in every respect, including texture,color, flavor and keeping qualities.

I claim:

1. The process of making a preserved avocado food product whichcomprises: subjecting avocado meat to lactic acid bacilli'fermentationto produce a slight acidity and form a product substantially free fromenzymes tending to cause discoloration; and thereafter pressing saidproduct to express therefrom liquid consisting principally of Water andcontaining a minor proportion of oil, until the water content of theproduct is reduced to below 60%, to form a food product of cheeselikeconsistency containing solid constituents of the fermented avocado meatand having a higher oil content than the original avocado meat.

2. The process of making a preserved avocado food product whichcomprises: subjecting avocado meat to lactic acid bacilli fermentationin the presence of an aqueous solution of sodium chloride to produce aslight acidity; leaching the fermented avocado meat with water to reducethe sodium chloride content theerof to a palatable level; and thereafterpressing the product to express therefrom liquid consisting principallyof Water and containing a minor proportion of oil, until the watercontent of the product is reduced to below 60%, to form a food productof cheeselike consistency containing solid constituents of the fermentedavocado meat and having a higher oil content than the original avocadomeat.

3. The process of making a preserved avocado food product whichcomprises: subjecting avocado meat to lactic acid bacilli fermentationin the presence of an aqueous solution of sodium chloride to produce aslight acidity; leaching the fermented avocado meat with water to reducethe sodium chloride content thereof to a palatable level; and thereafterpressing the product to express therefrom liquid consisting principallyof water and containing a minor proportion of oil, and continuing theexpression of liquid until the rate of expression of oil becomes aboutequal to the rate of expression of water, to form a food product ofcheese-like consistency containing solid constituents of the fermentedavocado meat and having a higher oil content and a lower water contentthan the original avocado meat.

4. The process of making a preserved avocado food product whichcomprises: subjecting avocado meat to lactic acid bacilli fermentationin the presence of an aqueous brine having a specific gravity between 10and 20 B.; continuing such fermentation until the pH is below 6 and thefermented avocado meat is substantially free from enzymes tending tocause discoloration thereof; then leaching the fermented avocado meatwith water to reduce the salt content thereof to a palatable level; andthereafter pressing the product to expel liquid consisting principallyof water and form a product of cheese-like consistency having a lowerwater content and a higher oil content than the original avocado meat.

LAURENCE E. HARRISON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,001,253 Crolbois Aug. 22, 19111,249,511 Saxe Dec. 11, 1917 1,698,294 Beckman Jan. 8, 1929 2,322,880Pollak June 29, 1943 2,325,327 Lachle July 27, 1943

1. THE PROCESS OF MAKING A PRESERVED AVOCADO FOOD PRODUCT WHICHCOMPRISES: SUBJECTING AVOCADO MEAT TO LACTIC ACID BACILLI FERMENTATIONTO PRODUCE A SLIGHT ACIDITY AND FORM A PRODUCT SUBSTANTIALLY FREE FROMENZYMES TENDING TO CAUSE DISCOLORATION; AND THEREAFTER PRESSING SAIDPRODUCT TO EXPRESS THEREFROM LIQUID CONSISTING PRINCIPALLY OF WATER ANDCONTAINING A MINOR PROPORTION OF OIL, UNTIL THE WATER CONTENT OF THEPRODUCT IS REDUCED TO BELOW 60%, TO FORM A FOOD PRODUCT OF CHEESELIKECONSISTENCY CONTAINING SOLID CONSTITUENTS OF THE FERMENTED AVOCADO MEATAND HAVING A HIGHER OIL CONTENT THAN THE ORIGINAL AVOCADO MEAT.